1. Field of the Invention
The invention relates to a control apparatus for a vehicular drive apparatus that includes an engine and a motor. More specifically, the invention relates to a technology in which the operating point of an engine and the operating point of a motor are determined based on the characteristic of a vehicular drive apparatus.
2. Description of the Related Art
A control apparatus for a vehicular drive apparatus that includes an engine and a motor is available. The control apparatus determines the operating point of the engine and the operating point of the motor based on the characteristic of the vehicular drive apparatus.
An example of such a control apparatus for a vehicular drive apparatus is described in Japanese Patent Application Publication No. 9-98516 (JP-A-9-98516). The vehicular drive apparatus includes a motor that is operated by electric energy stored in an electric power storage device, and an engine that is operated by combustion of fuel, as power sources for driving a vehicle. The control apparatus determines the operating point of the engine and the operating point of the motor based on the characteristic of the vehicular drive apparatus (for example, the system efficiency of the entire drive apparatus, which includes the energy conversion efficiency of the motor and the fuel consumption of the engine), to improve both of driveability and fuel efficiency.
However, when the operating point of the engine and the operating point of the motor are determined, no consideration is given to the fact that motor noise occurs due to the rotation of the motor when a power running control or a power-generation control is executed, or gear noise occurs with regard to gears of a drive system, which are engaged to transmit power, for example, gear noise occurs due to engagement of gears in a planetary gear unit that constitutes a portion of the drive apparatus. Therefore, a new problem may arise that the motor noise or the gear noise noticeably occurs at a specific operating point of the engine or at a specific operating point of the motor.